Does the sound of the forest change over time?

Bernie Krause knows.

The expert bio-acoustician has spent decades recording natural sounds all over the world, including one particular section of forest between Napa and Sonoma valleys.

Over a ten year stretch, from 2004 to 2014, he’s noticed a major change in the biophony of the section of forest where he records.

Listen in to hear the startling changes.

It should be noted that Krause uses high-end recording gear when capturing these sounds at Sugarloaf Ridge State Park. And he follows strict standards, like taking the recordings at the same time of day and using the same settings, so audio tracks can be compared from year to year with credibility.

“Spring at that spot is occurring two weeks earlier than when I started in the mid-90s,” Krause said.

He warns that it’s too early to draw major conclusions from his recordings, but one theory is that climate change is impacting bird migration patterns through this section of California.

“The biophony is a strong indicator of habitat viability. Think of it as the voice of the natural world,” he says. “Right now at that particular spot, the narrative expressed through that voice is not robust.”

One thing that definitely stands out in these records is the impact of the current drought. In 2004, and 2009, the water of the nearby stream is loud and sounds as if it is moving swiftly. Yet in 2014, the water can barely be heard at all.

Krause intends to continue his annual recordings in Sugarloaf Ridge State Park for years to come.

Here are the individual tracks by year, so you can listen again.

Learn more about Bernie Krause and Wild Sanctuary.

KQED Science Editor Craig Miller contributed to this report.

Listen Closely As This California Forest Falls Eerily Quiet Over 10 Years 4 November,2014Olivia Allen-Price

  • likesbirds

    The article should specify if his recordings were done at the same time of day or not.

    • Olivia Allen-Price

      Great point. I added some detail into the story. Krause has taken all of these recordings at sunrise. – Olivia

  • Carol Carson

    The reason the song birds are gone in Santa Cruz- neighbors that let their cats out and feral cats- now Lighthouse Field is silent except for the crows.

  • Jennifer

    It’s not just that it’s quieter, but there is a different set of species each time. Wild Turkeys are prevalent in the last recording and they use some forest as roosting areas but they are associated with at least some open habitat, varying by subspecies. It seems the landscape would have to be different. I’m a fan of mature woods because they are the hardest to achieve, but songbirds don’t collect dollars and turkeys do. “Restoration” of habitat for game birds, which may include removal of mature forest to provide the grazing areas needed are seen as an improvement by some. It all depends on what you value.

    • There are plenty of pastures in California.

      • Bill McKain

        That’s what I thought too Amy

    • Napalmfodder

      Values change, especially when forests die.

  • OutruntheWind

    The drought likely has contributed some, especially to the lack of flowing water.

    • Napalmfodder

      BRILLIANT!!! What has contributed to the lack of flowing water? Lack of rainfall?? Or perhaps overuse of water sources by increased population as well as total disregard for limiting consumption of resources? The lack of sunlight at night could likely be contributed to the shadow of the earth. People only see what’s in front of them.

  • Maximus Dali

    This means absolutely nothing – lol

    • Napalmfodder

      Most things mean nothing to ignorant people.

  • Singing Luna

    It is sad to think that future generations may only know what birdsong sounds like by listening to recorded versions. Thanks for the interesting article and sharing of “biophony” recordings.

  • PickUppd_22

    no discussion on the drought?

  • Darla Doxstater


  • Sabbie


    • Bill McKain

      destruction of habitat, both in Central/South America and here in the US is the main driver here Sabbie. While the west does not have nearly the diversity of songbirds as the east – it’s been disheartening to view the crash of songbirds that has occurred here over the last 30 years.

    • That’s one of the most benign pesticides humans use. As measured by LD-50, it’s less toxic than table salt. There’s a nice chart here comparing a variety of substances, including glyphosate:

      Of course LD-50 is just one measure, but the generalization that it’s safer than just about anything else we’ve ever used in agriculture remains true by many other measures. Via wikipedia:

      When glyphosate comes into contact with the soil, it can be rapidly bound to soil particles and be inactivated. Unbound glyphosate can be degraded by bacteria. Glyphosate and its degradation product, aminomethylphosphonic acid (AMPA), residues are considered to be much more toxicologically and environmentally benign than most of the herbicides replaced by glyphosate.

      • Napalmfodder

        Making arguement for poison that is less harmful than other poison is as absurd as comparing pre-meditated murder to murder in a moment of anger.

        • Here’s a paradigm shift which more accurately reflects biological reality: Poison is a property of doses, not chemicals.

          All substances are poisonous in sufficient quantity, including water and oxygen. Would you object to the application of water to crops because people occasionally die of water poisoning? That’s an absurd proposition because as you surely know, it’s impossible to grow crops without water.

          All substances are poisons in sufficient quantity. Poison is not an intrinsic property of specific chemicals, but of specific doses.

          A surprisingly large number of food plants are cyanogenic, meaning they contain some form of cyanide:

          You might wrongly believe that cyanide is intrinsically a poisonous substance, but it isn’t. Once you understand the mechanism of cyanide poisoning, it becomes clearer why.

          If you consume too much cyanide, your mitochondria are deprived of cytochrome c oxidase which is essential to cellular respiration. In large doses, cyanide effectively suffocates you at the cellular level. However, in smaller doses as might be found in almonds, you suffer no noticeable ill effects. There isn’t enough cyanide to take up enough cytochrome c oxidase to harm any of your mitochondria. Even if a few mitochondria were destroyed by the small dose of cyanide that you consume, you have thousands of mitchondria per cell and can suffer the loss of a few with no ill effects to the cell itself (they’re soon enough replaced by the other mitochondria which are always replicating themselves).

          There is a poisonous dose of every pesticide approved for use in organic agriculture. For example, it takes twice as much glyphosate to kill a rat as it does pyrethrum, an organic-approved pesticide. The organic approved “natural” pyrethrum pesticide is at least twice as poisonous as the synthetic pesticide glyphosate (some formulations of pyrethrum are closer to 25x as toxic as glyphosate).

          Once you understand that every substance has a poisonous dose, your perspective necessarily shifts from one of complete risk avoidance to one of risk management. It isn’t possible to grow food without using chemicals (including water, fertilizer, etc.) that have poisonous doses. If you want food, you have to accept some risk. For some chemicals like water, the risk of poisoning via food consumption is effectively zero. Likewise for glyphosate and even pyrethrum. You are unlikely to consume a lethal dose of either pesticide residue from application to the crop (but as noted previously, LD-50 isn’t the final word toxicology and there are other effects of mutagenicity, teratogenicity etc to be considered).

  • Iyad Qumseya

    Half of the Wildlife is gone the past 4 decades, is that open for discussion too?
    We need Awareness and respect towards what we cannot replace.

    • Stefani

      Completely agree. This breaks my heart.

  • Birdfish

    I’ve made recordings in my backyard here in Berkeley ’09 and again in ’14. Same time of year, same hour of the day. The differences are staggering, much less diversity of species in terms of birdsong. I have a six year old daughter and I worry about what will be left for her.

  • Mike from the woods

    There’s very little information here, certainly not enough to support the implied conclusion about there being less wildlife. Each recording is 30 seconds long, a snapshot, and these show only that the woods sound different at different times. An hour spent quietly listening anyplace in the woods yields the same result. The observation that spring occurs earlier than it did 20 years ago may be true, and would be a significant indicator of large-scale change, but these recordings, as interesting as they are, don’t show that.

  • Mike

    Soundcloud links don’t work. And there is a picture of a forest. Along with your description. Cool story.

  • It’s California. We’re in a drought. 2004 iirc was an average year.

    • Napalmfodder

      We are in a major drought mostly due to human consumption. We dam up streams that used to flow and change the course of wildlife so we can flush our toilets and water our walnut groves.

      • We haven’t built much in the way of dams or reservoirs in over 10 years (and really anything substantial since ’99).
        While you are correct that part of it is man-made (squeezing an extra 10M people without building sufficient dams is pure folly), we managed until the rain stopped. It’s an unusually dry year. The Sugarloaf Ridge State Park feeds into Napa valley and should be unaffected by dams. It’s dry anyway.

  • Noreen P.

    I live 20 minutes from that very spot in the Skyhawk neighborhood down Hwy 12 in Rincon Valley. I’ve noticed a significant decrease in birdsong in my own backyard. My family moved to this house in Spring 2001. We live on in a house with a backyard that is on a hill with a creek at the bottom. There is a lot of wildlife that lives amongst the trees and blackberry bushes that line the creek -various birds, raccoons, frogs, turkeys, crickets.. When we first moved in, we’d wake up to a loud and lively chorus of birds and be seranaded to sleep by an orchestra of chirping crickets and frogs. 13 years later, the sounds are still there.. but the volume has been turned down significantly. Before, you couldn’t really ignore it. Now, you have to listen for it. I wish. I’d gotten recordings, too. The difference is pretty astounding.

  • Maringuy

    We are in the midst the biggest drought in 100 years of keeping records. I think my 6th grade daughter could put the pieces together between climate change – drought – flowing streams – birds and wildlife sounds.

  • djsully

    DROUGHT – the period is too short to draw firm conclusions. CA runs in roughly 7 year drought cycles, so over a 14 year period we MAY see a pattern develop that mirrors the cycles in some way. Applying this filter would be a useful study

  • GetReal

    That’s what Rachel Carson meant by “Silent Spring”.

  • Salvador Yanez-Ruiz

    Everyone is up in arms about climate change and how humans are hurting nature, yet you don’t do a thing about it because you don’t even realize how you’re contributing to it. Do your research and wake up people, for our own sake. I’ll give you a starting point. Research how the meat industry affects deforestation and pollution. Your hybrid can’t counteract the damage all the methane gas meat industry animals produce. Forests are cut down to provide crops and housing for these forcibly enlarged populations of cows, pigs, etc. Stop your sickening behavior.



Olivia Allen-Price

Olivia Allen-Price is producer and host of the Bay Curious series. Prior to joining KQED in 2013, Olivia worked at The Baltimore Sun and The Virginian-Pilot in Norfolk, Va. She holds degrees in journalism and political science from Elon University. She loves to talk about running, ice cream and curly hair.

Follow: @oallenprice

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